The Strong Effect of Hydrogen


The strong effect of hydrogen was published for the first time in 1985 in Optics Communications v.56, No.4, p.279.


In 1977, the American physicists Vetter and Nerheim observed that small quantities of HCl added to the neon buffer gas in the copper chloride vapour laser led to a 15% increase in laser pulse energy; also, that small quantities of hydrogen resulted in reducing laser pulse energy. In 1980, the Russian scientist Bokhan found that small additives of hydrogen to the buffer gas of neon in the elemental copper vapour laser led to a 20% increase in average laser output power. Both scientific announcements had not provoked serious interest in the use of hydrogen additives to raise the output power in copper lasers. The subsequent experiments could not reproduce the results published by these authors; even the opposite effect of reducing the laser output power by hydrogen was observed.

Nature of the scientific achievement

At the laboratory of N. Sabotinov, in the course of the investigations of the energy parameters and technology for producing long-lived copper bromide vapour lasers, it was found that small quantities of hydrogen (0.3-0.6 Torr), added to the neon buffer gas in the laser active medium resulted in:

  • doubling laser output power

  • doubling laser efficiency

  • significant improvement (up to almost Gaussian) in the power radial distribution in the laser beam which leads to raising strongly laser beam quality

  • increasing the active element impedance which enables its better matching with pulse supply block

  • the increase in the laser tube impedance enables to raise the density of copper active atoms as at the same time, the high electrical potential of electrodes keeps; thus a main problem in copper lasers is solved

Uses of the scientific achievement

The discovery of the strong effect of hydrogen has exerted a significant influence on the development of copper lasers. It has both scientific and practical values. The interest in the use of hydrogen in the copper lasers has grown greatly. The result showing that the admixtures of hydrogen have an optimum concentration for a positive effect on laser generation processes has been of a significance importance. At concentrations larger than the optimum, the effect is negative. This namely explains why the effect published in 1977 and 1980 was weak, also the fact that nobody was successful in recovering these results during five years.
Results obtained after the publication of 1985 have given the start of using widely the hydrogen effect to attain high laser output powers. Chinese and Japanese scientific research teams use the hydrogen effect to raise the output power of the copper vapour laser. At the Livermore Laboratory in the USA, applying the hydrogen effect has been of great importance to increasing the output power and laser beam quality in the world's most powerful copper laser system for separation of uranium isotopes. N.Sabotinov has received from the Leader of the Livermore Laboratory a congratulation letter for the discovery of the hydrogen effect.
The strong hydrogen effect has been introduced into the practice of all laboratories where high-power copper lasers are created in countries such as Great Britain, Japan, Israel, Australia, China, USA, etc.
The physical explanation of the hydrogen effect on population inversion processes in the active plasma medium of copper lasers is of a particular scientific interest. To explain the hydrogen effect has proved to be a difficult task. At the Laboratory of Prof.N.Sabotinov, theoretical explanation of the hydrogen effect is developed and relevant experiments are conducted.
Great interest had been manifested by a team of scientists at the Institute of Physics, the Russian Academy of Sciences, Moscow, who started active studies of the processes occurring in the laser medium. After 1986, many scientific works on the hydrogen effect were published. In almost all of them as the principal paper on this subject is pointed the initial publication in Optics Communications v.56, No.4, p.279, 1985.
To the hydrogen effect is devoted a large part of the monograph "Metal Vapour Lasers", 1999, by C. E. Little. Here the discovery of the hydrogen effect and its application and studies are described in detail.
In his review paper on copper lasers, C. Webb of the University of Oxford also paid much attention to the strong hydrogen effect and its significance for the development of copper lasers.